It is often desired to carry out a heat exchange operation with a stream at pressure without significantly degrading the pressure of the stream. One such example is the rejection of the heat of compression from a stream of compressed air which is intended as feed for an air separation plant. Another example is the rejection of the heat of compression from compressed natural gas which has been compressed to pipeline pressure. When the heat exchanger to accomplish this task is placed between stages of a multistage compressor it is often termed an intercooler.
Effective heat exchange is carried out by efficient contact between hot and cold media. One way to achieve such efficient contact is to arrange even distribution of the flowing media with respect to each other. This is especially the case for an intercooler where only one pass can be made due to the pressure loss considerations. Pressure loss may be caused by flow disturbances, areas of flow recirculation, drag of the core, and changes in area. A successful intercooler must provide good heat transfer while keeping pressure loss to a low level.
The above-described considerations have been addressed by the prior art. U.S. Pat. No. 3,532,160--Garrison describes an intercooler with a baffle to separate the inlet and outlet ports and a perforated plate which acts as a gas distribution means. The baffle is at a right angle to the intercooler length. The perforated plate achieves good gas distribution but imparts a relatively high pressure drop to the compressed stream.
U.S. Pat. No. 4,415,024--Baker discloses an improvement to the Garrison system wherein the separating baffle is diagonally oriented with respect to the intercooler length. This diagonal baffle has the dual purpose of separating the inlet and outlet ports and distributing the compressed gas flow. However, the separating plate taught by Baker allows some of the inlet gas to flow away from the intended direction of the tube bundle because the area behind the inlet port is open. Similarly, on the outlet side, flow may recirculate in a non-useful manner due to the configuration of the baffle. This non-useful flow causes an unnecessary loss of pressure energy.
It is therefore an object of this invention to provide an improved heat exchanger for use with a stream at elevated pressure.
It is a further object of this invention to provide an improved heat exchanger having relatively even flow distribution while not imparting an excessive pressure drop on the compressed gas stream.